Dyeable polymer blends, including copolymers of acrylonitrile with alkenyl haloacetates



DYEABLE POLYMER BLENDS, INCLUDING CO- POLYMERS OF ACRYLONIE WITH ALKE- NYL HALOACETATES Alfred B. Craig and George E. Ham, Decatur, Ala.

No Drawing. Application March 2, 1953, Serial No. 339,912

8 Claims. (CL 26045.5)

pending application Serial No. 208,088, filed January 26,

1951, Patent No. 2,719,834, issued October 10, 1955.

It is well-known that polyacrylonitrile, and various copolymers of acrylonitrile and other olefinic monomers, can be spun into synthetic fibers having unusual physical properties. Because polyacrylonitrile and the many copolymers of acrylonitrile are almost inert chemically, conventional dyeing procedures are not useful in processing them. Many copolymers of acrylonitrile have been prepared using as the comonomers substances which impart dye-ailinity. copolymers of this type are not always satisfactory because of the excessive cost of the dye-receptive comonomers and because the introduction of such substances often depreciates the desirable fiber-forming characteristics of the copolymer.

The primary purpose of this invention is to provide a new acrylonitrile polymer composition which has the chemical and physical properties of polyacrylonitrile and which can be made completely dye-receptive by simple readily practicable procedures. A further purpose of this invention is to provide a means for converting non-dyeable acrylonitrile polymers into a dye-receptive form. A still further purpose is to provide new general synthetic fibers.

In accordance with this invention it has been found that polyacrylonitrile and other non-dyeable polymers of acrylonitrile, for example the copolymers of over 80 percent acrylonitrile and up to 20 percent of other olefinic monomers, such as vinyl acetate, styrene, alpha-methylstyrene, methacrylonitrile, vinyl chloride, vinylidene chloride, and the various alkyl acrylates, alkyl methacrylates, alkyl fumarates, and alkyl maleates wherein the alkyl groups have up to four carbon atoms may be readily 1 converted into dyeable polymers. This is achieved by ,blending the non-dyeable polymers with polymeric com positions derived by the polymerization of unsaturated esters of haloacetic acid which polymeric compositions have been previously treated or are thereafter treated in the blended form with thiourea and alkyl substituted thioureas. Suitable monomers for polymerization into the useful polymeric compositions are those represented by the generic formula:

wherein X is a halogen atom and R is a radical selected from the group consisting of vinyl, allyl, methallyl and isopropenyl. Suitable monomeric substances include vinyl chloroacetate, allyl chloroacetate, methallyl chloroacetate, isopropenyl chloroacetate, and the corresponding bromine analogues.

nited States Patent tain the desired end result.

" ice The proportions of the unsaturated halogen containing polymer will depend upon the degree of dye-receptivity desired, and upon the proportion of the alkenyl chloroacetate in the blending polymer. In general, it is desirable to have from two to 20 percent of the fiber-forming composition in the polymeric form of the alkenyl chloroacetate. Thus, if the blending polymer is percent alkenyl chloroacetate polymer, from two to 20 percent will be required to develop suitable dye/receptivity. If a copolymer of the chloroacetate and another monomer is used, proportionately more will be required to ob Polymers of more than 30 percent of the haloacetate monomers and up to 70 per cent of another olefinic monomer may be employed. These other monomers maybe acrylonitrile, methacrylo:

nitrile, vinyl acetate, vinyl chloride, vinylidene chloride,

'of the alkenyl chloroacetate, for example, methallyl chloroacetate.

The base polymers are preferably prepared in an aqueous medium in the presence of a water-soluble peroxy catalyst and in the presence of an agent which maintains the polymer formed in a fine but granular dispersed condition. Suitable peroxy catalysts are thealkali metal persulfates and suitable dispersing agents are the alkalimetal salts of sulfonated hydrocarbons. Polymerization may be conducted by batch procedures, by continuous procedure or by combination of these procedures. A preferred method of preparation involves a batch procedure wherein the desired monomers are mixed and charged gradually throughout the polymerization. Unusually uniform polymers may be obtained by also charging the catalyst and emulsifier continuously or in increments throughout the course of the reaction. More uniform polymerization conditions may be achieved by operating at uniform temperatures, for example the reflux temperature of the medium, especially if the operation is so conducted as to provide a constant temperature at reflux.

If desired, the polymerization reaction may be conducted in the presence of a redox agent, for example, sulfur dioxide, sodium bisulfite, sodium thiosulfate, or other sulfur compounds in which the sulfur is present in an oxidizable condition. Other optional procedures may involve the use of regulators which serve as chain terminators to prevent the formation of very high molecular weight increments, agents of this type being t-dodecyl mercaptan, thioglycolic acid, and dithioglycidol.

The procedure for preparing blending polymer is substantially the same as that used in the preparation of the base polymer. However, other known polymerization methods can be used, such as mass polymerization and suspension polymerization.

In order to convert the fiber-forming blends containing an increment of the chloroacetate polymers, it is necessary to react the chloroacetate group with a compound which will introduce amido nitrogen atoms. Suitable reagents of this type are thiourea and the various alkyl-substituted thioureas.

In this manner nitrogen atoms are introduced into the molecule which will provide nuclei for chemical reaction with conventional acid dyestuifs. Suitable compounds of this type for use in the development of dye-receptivity are thiou'rea and alkyl substituted' thioureas having the formula:

RNH-O;NH-R

wherein'R andR each 'repres'ent's'hydrogen; alkyl radical having less tlian'five carbon atoms, or' alkenyl radicals having less than five carbon atoms. R" and R may represent the same or different radicals; thioureas falling within the scope of the above 'formula'are syrn-dimethylthiourea, sym diisopr'opylthiourea, N-ethylthiourea, N methylthiour'ea', N-all'ylthioure'a, sym-diallylthioiirea; 'N-vinyl thiour'ea, N metliallyltliiourea, N-isopropenylthiourea," and "N-ethyl, N'-methyl thiour'ea.

The polymer may'be'treated withthethioureas in granular'solid state, in seliitib'n" in"a"siiitable' solvent, and in tliefor'mof a'spunfibe'rl' Ifthe polymer is'in solid'form, obviously only the surfacewill be reacted chemically, and if the polymer is" treated in solid' form before" spinning the activated surface lmay be substantially dilutedwhen the'polymer' is dissolved and reformed into fibers. Accordingly, the most 'efiective precedure involves chemical treatment insoluti'oii' state. The' modification may take place'in the spinning solution from which the fibers will ultimatelybe preparedf Accordingly, the polymers are eachdissolvfed, separate or together in suitable'solvents, for example; N,N-diihethylformamide, ganima-butyrolactorie; ethyleiie carbonate; orother conventional: polyacrylonitrile solvents. On the contraryvthe modification of the hal'oacetate cbntaihirig blending polymer with the thioureas may be carried out while the blending-polymer is in solution in one o'f'the above-named solvents, and the resulting treated polymer's'olution can then be blended witha' solution of the base polymer in the same, or compatible, Sblvilis.

In the'practice'of this invention thedyeable fiber-formingcompo'sitioiis' are p'rep'a'redby mixing the solid polymers in suitable coavemion'armechanical mixers, for example', Banbu'ry' mixers, roll'rr'iills, ordough mixers In general, it isdes'irable'to' add the solvents or plasticizers for"fiber forming'acrylbnitrile polymers. The intimate mixing'of the"polym'ers"o'r blehde'd polymers with the reagent may inducethe"'re'a'ction' of substantially all of the chloroacetate group's: Less thorough mixing, especially ifthepol'ym'er'soltltionsafe quite viscous, will induce th'e'reaction'ofonlya sman'prdpoaion, for example from five-to 50 percent, of'the' chloroacetate groups with the reactant. 'Und'r'such conditions if will'be necessaryvto add murder the crflerdaeefarvpolymers in order to develop the desirable" extentofdy-receptivity. Thus, the manner of mixing andthevis'c' y of the Blending mixture must be considered inselect'ih'g theproper proportions of polymers.

The new blended" compositions may be fabricated into synthetic fibers byconveiitibnahwet or'd'ry spinningprocedures; After-stretching the'fibers to develop. the necessary orientation and nieineidennensne strength, and

thereafter shrinking thefibersto' improve their thermal resistance, valuable general purposefibe'rs are obtained.

Further details of this invention are set forth with respect to' the following'exa'rnples:

Example I A blend of 1.2 grams of polyvinyl chloroacetate and 13:9 grams 'ofa copolymefof 95' percent of acryloni trile andfive percent of vinyl acetate" was prepared by mixing in 85 gra'm'sof' N;N-dimethyla'eetainide"and fibers were spuntr oni the solu'tio a A'sk'ei-n'of fiber (0.7 gram") was treated for three hours at 100 C. in a dyebathcontaining=32 cc. of water,- 0.014"-gram of Wool Fast Scarlet G. upr adye,- -.07; gramof sulfuric-acid, and 0.048 gram of thiourea The-dye acceptance wassu'ch that the dyeba'tli was exhausted by thetreatment'.

Examples of 4V Example II A dry blend of 2.6 grams of a copolymer of 67.4 percent of acrylonitrile and 32.6 percent of vinyl chloroacetate, and 14.4 grams of a copolymer of 97 percent of acrylonitrile and three percent of vinyl acetate was dissolved in. 83 grams of N,N-dimethylacetamide. The fibers spun from this solution were found to have a tenacity of 3.3 grams per denier. of this fiber was treatedin a dyebath containing46*grams of water, 0.023 gram of Wool FastSc'arlet G Supra dye, 0.115 gram of sulfuric acid and-0:115" gram of thiourea. A virtually complete exhaustion of the dyebath wa obtainedinthreehours' at 100 C.

Example III A mixture of 11.6 grams of polyvinyl chloroacetate and 77.9 grams of a copolymer of 97 percent of acrylonitrile and three percent of vinyl acetate was prepared by mixing thesolid polymers. The mixture so-obtained was added to 468 grams of N,N-dimethylacetamide and stirreduritil complete solution to'ok place. Fibers prepared by the procedure described in preceding examples were dyedin a dyebathcontaining. 0.05 percent of Wool Fast Scarlet G Supra-dye-and 0.25 percent of-"sulfuric acid. 40 cc. of the dyebath was used-for each'gramof fiber. Several different treatments were made using 0, 5, 10," 20, and 50 percent of"thio urea based on fiber weight. After one hour at 1'00C. the sample dyed in the absence of' thiourea showed essentially no dye pickup. Although all of the remaining samples were readily dye-receptive, the optimum result was achieved with about ten percent ofthiourea (based on fiberweight) in the dyebath.

Example 1V Fibers (1.0 gram) composed ofablend-ofa copolymer of 97 percent acrylonitril'e-ir percent vinylacetate and a copolymer of 60.5 percent acrylonitrile-395' percent methallyl chloroacetate, with an" overall methallyl chloroacetate'content of 8 percent, were immersed for- 30 minutes at 95 C.- in a bath consistingof 60 mls. ofwater, 1.3 rnlsz of twop'ercent Wool' Fast- Scarlet, 5'.9'-mls. of three percent sulfuric acid, and' 0.1 gram of=syrndimethyl thiourea: Th'e dyebath was exhausted by the treatment and the fiber was dyed a deep scarlet.

Example V The procedure of Example IV was repeated using Alizar inLight Blue 4 GLand-Wool Fast Yel10w,- except that 0.2-g. of-'thiourea was used in the dye bath. Deep shades were produced on the fibers.

Example VI The-procedure of Example IV was repeated'with the exception that an allyl chloroacetate copolymer was substituted for a methallyl' chloroacetate copolymer. Fibers dyed as in-Exam-ple IV were dyed deep scarlet with Wool Fast Scarlet.

Example VII- The" procedure for-*Exam'ple IV was repeated, but N- allylthiourea was subst-ituted for thiourea in the dyeing- 1. A-dyeable fiber-spinning:composition comprising a blend of (A) a polymer of at least percent'by weight A 1.15 gramskein of acrylonitrile and up to 20 percent of vinyl acetate and (B) a polymer of at least 30 percent by weight of an alkenyl haloacetate of the structure:

wherein R and R each represents a member selected from the group consisting of hydrogen and alkyl radicals having less than five carbon atoms, the polymers being blended in such proportions that from 2 to 20 percent of the total weight is the said alkenyl haloacetate.

2. A dyeable composition as defined in claim I wherein the haloacetate is vinyl chloroacetate.

3. A dyeable composition as defined in claim 1 wherein the haloacetate is allyl chloroacetate.

4. A dyeable composition as defined in claim 1 wherein the haloacetate is methallyl chloroacetate.

5. A dyeable composition as defined in claim 1 wherein the haloacetate is isopropenyl chloroacetate.

6. A dyeable composition as defined in claim 1 wherein the compound is thiourea.

7. A dyeable composition as defined in claim 1 wherein the compound is sym-dimethylthiourea.

8. A shaped article of the composition as defined in claim 1.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A DYEABLE FIBER-SPINNING COMPOSITION COMPRISING A BLEND OF (A) A POLYMER OF AT LEAST 80 PERCENT BY WEIGHT OF ACRYLONITRILE AND UP TO 20 PERCENT OF VINYL ACETATE AND (B) A POLYMER OF AT LEAST 30 PERCENT BY WEIGHT OF AN ALKENYL HALOACETATE OF THE STRUCTURE: 